Commercial food processing facilities and the food products moving through such facilities must be maintained in a scrupulously clean condition. One method of achieving this high level of cleanliness is by means of cleaning the processing equipment used in the facility with high-pressure, hose-down cleaning with steam, hot water and/or chemical solutions. During the course of this cleaning process, electric motors utilized in the manufacturing operation are exposed to harsh, wet, corrosive and/or oxidative conditions. These “washdown motors,” as they are referred to in the industry, are also used in chemical manufacturing facilities and other similar environments.
This combination of steam, heat, moisture and other corrosive factors typically results in very short life cycles for washdown motors. In the course of the cleaning process, the level of humidity in the facility being cleaned increases and corrosive chemicals can become dissolved in the wastewater. The resultant high humidity, particularly in combination with dissolved chemicals in the atmosphere, produces a highly corrosive environment and the effective life of a conventional motor can be drastically reduced because of water or other fluid contaminants entering the motor and causing either mechanical or electrical failure. It is not uncommon for such motors to fail within a matter of a few months; in some applications failure occurs in a matter of days or weeks. This need to constantly replace washdown motors is an added expense to food processors and other users of such motors. Additionally, the need to suspend operations while repairs are made is disruptive to the flow of product through the processing facility and results in increased labor costs. In industries which have continuous processes in operation, the down time experienced for the repair can have significant detrimental consequences.
Electric motors typically include an electrical inlet that receives the electrical wires that provide power to the motor, and, if adequate measures aren't taken, such electrical inlets often serve as an entry point for moisture to enter the motor. Certain current designs for electric washdown motors include an external conduit box or junction box that is in communication with the electrical inlet of the motor and houses the wire-to-wire electrical connections between the electrical wires used to provide power to the motor and the electrical wires that extend from inside the motor into the junction box. In such motors, a seal is positioned around the electrical wires passing from inside the motor to the junction box to prevent water from entering the electrical inlet of the motor. Additionally, the individual wire-to-wire electrical connections between the electrical wires and the power wires are sealed within the junction box so the presence of electrically conductive liquid within the junction box does not cause a short circuit or corrode the wire-to-wire electrical connections. For example, the bare wire ends may be crimped inside a metal tube to make the electrical connection and sealed with a heat-shrinkable polymer tube lined with a layer of hot-melt adhesive to seal the connection.
However, this arrangement provides several disadvantages. For example, in a situation where a motor fails in use during a production process, time is of the essence to replace the electrical connections because motor downtime creates a significant loss in production, which can have a significant economic impact. For instance, the actions required to disconnect and remake the sealed wire-to-wire electrical connections are very time consuming. Also, for a dual voltage three-phase motor, there may be four sealed wire-to-wire electrical connections (for low voltage) and six sealed wire-to-wire connections (for high voltage), which means multiple crimp connections of wires must be completed and sealed with heat-shrinkable polymer tubing. Additionally, because the electrical connections are sealed inside of a junction box, the time it takes to remove the junction box (which usually includes multiple separate screws) further adds to the length of downtime and possible loss of production time.
Therefore, there is a need for an improved electric motor that provides an improved arrangement for making and protecting the electrical power connections to the motor and which can be used in washdown applications. Additionally, there is a need for an electric motor that provides an improved arrangement for making and/or replacing the electrical connections of the motor to reduce the time it takes to make and/or replace the electrical connections of the motor while maintaining washdown resistance. There is also a need for an improved electric motor that can withstand constant washings with water and/or other cleaning agents and exhibits increased resistance to the ingress of moisture into the motor interior that results in an extended life for the motor when used in adverse conditions, such as the repeated washings experienced in food processing plants.